Telescoping switch

ABSTRACT

This is a telescoping switch having a spring in the plunger assembly which requires greater force for compression than the spring in the contact assembly with the plunger assembly directly associated with the contact assembly. The switch includes a plunger assembly in which a first plunger is telescopically associated within a second plunger and the second plunger is telescopically associated within a divider.

United States Patent Inventors Bela Bognat' Bellingham; Warren V.Gureghian, Watertown; Anthony R. La Scola, Bellingham, all of Mass.Appl. No. 33,565 Filed May 1, 1970 Patented Nov. 30, 1971 Assignee TRWInc.

Cleveland, Ohio TELESCOPING SWITCH 5 Claims, 4 Drawing Figs. I

U.S. Cl 200/159 R, 200/ 153 V Int. Cl H01h 13/52,

HOlh 3/48 Field 01 Search 200/159 R, 16 A, 153 V [56] References CitedUNITED STATES PATENTS 2,817,725 12/1957 Rochfort et a1 n 200/153 V UX2,899,511 8/1959 Fraser A. 200/16 A X 3,140,365 7/1964 Voland 200/16 A3,485,975 12/1969 Long 200/153 V UX FOREIGN PATENTS 700,140 1 1/1940Germany 200/1 Primary Examiner- Robert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorneys- Philip E Parker, Gordon Needleman, JamesR.

O'Connor, John Todd and Hall and Houghton ABSTRACT: This is atelescoping switch having a spring in the plunger assembly whichrequires greater force for compression than the spring in the contactassembly with the plunger assembly directly associated with the contactassembly. The switch includes a plunger assembly in which a firstplunger is telescopically associated within a second plunger and thesecond plunger is telescopically associated within a divider.

0 7 AN 3 7 6 S mwmm 2 0 S 4 T 5 Y AEO 8 1 W X 8 m V R L WARREN v GURBELA B ATTORNEY 88 ANTHONY PATENTED HUV30 I971 TELESCOPING SWITCHBACKGROUND OF TI-IE INVENTION 1. Field of the Invention The type ofswitch described hereinafter is used in the appliance industryparticularly in household refrigerators and other appliances. Thisswitch may also be used in any location in which a door switch isutilized, such as automobiles. The switch must be one that isself-adjusting. In other words, it should provide for overtravel causedby variations in cabinet or door construction. In the refrigeratorfield, the switch is usually mounted on the breaker strip in the cabinetand opening and closing of the door in relation to the cabinetphysically activates the switch. A switch in this position and for thisusage should also be constructed to prevent someone washing the switchfrom electrical hazards.

2. Description of the Prior Art The patent to Janos, US. Pat. No.2,658,968 describes a spring 12 in a switch plunger which acts as a lostmotion device on movement of the bellows 2.

The patent to Loesch, U.S. Pat. No. 3,172,981 described a switch spring25 which acts as a lost motion design after the plunger 28 is free totravel without causing movement of the contact 40.

Neither the Janos or the Loesch patents utilize a telescoping elementwithin which the spring moves and in which the plunger also moves.

The patents to Basso, US. Pat. No. 2,921,155, to Furman, US. Pat. No.3,249,727, and to Basso, US. Pat. No. 3,393,281 describe door switcheswhich have a telescoping element in operation with the plunger in whichthe telescoping element is moved inwardly on a one shot installationoperation to provide a self-adjusting feature. In the initial activationof this switch, the plunger is depressed by the door until its free endis in registry with the free end of the telescoping element upon theclosing of the door, the plunger in the telescoping element will bedepressed inwardly thereby being fixedly positioned within the door.Upon the opening of the door, the plunger will be returned to itsinitial position with the telescoping element fixedly positioned byfriction within the switch housing.

None of the telescoping elements of the patents mentioned hereinaboveare adequate to move back from the telescoping position.

SUMMARY OF THE INVENTION The switch includes a control carrying elementwhich floats between a plunger spring and a contact spring. The outsideend of the plunger spring butts against the plunger which is depressedby a door or the like. The plunger spring described affords a lostmotion on the plunger which is made in two telescoping parts so that thespring maybe compressed the full length of the two part structure whilethe telescoping plunger occupies only about two-thirds of the space inthe housing that would be required by a nontelescoping plunger.

An object of the present invention is to provide an appliance switchassembly which is readily installed.

Another object of this invention is to provide a switch having a twopart plunger the parts of which are telescopically associated.

A still further object of the invention is to provide a switch which iswater resistant while providing for overtravel of the plunger.

DESCRIPTION OF THE DRAWINgs FIG. 1 is a perspective of the switch.

FIG. 2 is a section of the switch shown in FIG. 1.

FIG. 3 is the outside section showing a different view of the switch inFIG, 2.

FIG. 4 is a section taken on line 4-4 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The switch 10 comprises an innerplunger 12, an outer plunger 14, a plunger spring 16, a divider 18, abody 20, a seal element 22, a case 24, a pair of fixed terminals 26, amovable contact 28, and a contact spring 30.

The plunger assembly includes the outer and inner plungers I4 and 12,plunger spring I6 and the divider 18. The inner plunger 12 comprising atubular body closed at one end and open at the other. An annular flange32 extends radially outwardly adjacent the open end. The outer plungerI4 is open at both ends, and lipped over at one end to provide aninternal circumferential shoulder 34 and has its opposite end thickenedon the external surface to provide a flange 36. The divider 18 comprisesa circular base portion 38 having a rod portion 40 extending axially andcentrally from one side and a cylindrical post portion 42 extendingaxially and centrally from the other side. A circular wall 44 extendsupwardly from the edge of the base portion 38 in spaced relation to therod portion 40. The wall 44 includes a forward edge. Four rectangularslots are formed through the base portion 38 up into the wall 44. Eachof the rectangular slots terminates near the forward edge of the wall 44and has a forward wall with a tongue 46 extending therefrom. The tongue46 is angled inwardly toward the rod portion 40. Four narrow slotsextend into the wall 44 toward the base portion 38 from the forwardedge. Both the narrow slots and rectangular slots are equally spacedaround the circumference of the wall 44, and are in staggered relationto each other.

The body 20 includes a cylindrical plunger holder or upper portion 48having a top surface and an annular flange 50 extending radially from anend and forming a right angle with the plunger holder 48. An aperture 52is formed axially and centrally through the plunger holder 48. A cavityis formed within the plunger holder 48 of greater diameter than theaperture 52 and into which the aperture 52 opens. Arced guides extenddownwardly from the plunger holder 48 adjacent the cavity and in opposedrelation with each other. An integral leg 54 extends from each side ofthe plunger holder 48 in opposed relation to each other and spaced fromeach other. Each of the legs 54 has transversely arced inner and outersurfaces and each of the inner surfaces has a vertical slot 56 formedtherein. An integral ring portion 58 joins the legs 54 and provides aplane which is in spaced, parallel relation to the annular flange 50.Two arms 60 extend from the ring portion 58 toward the flange 50. Thearms 60 are in spaced opposed relation to each other with a leg 54between them on each side as shown in FIG. 1, and each leg 54 has a freeterminal end as well as a knuckle. The vertical slot 56 is continuedthrough the ring portion 58. Each of the legs 54 is continued beyond thering portion 58 as a thinned external portion 62 including a rectangularopening 64 and a wing portion. The external portions 62 are joined by askirt portion 66 which extends from the ring portion 58 and forms aninternal shoulder 68 therewith.

The contact assembly includes the case 24, the fixed and movablecontacts, the contact spring 30 and the seal element 22. The case 24comprises a base portion 70 having an upstanding generally oval wall 72extending therefrom around its edge to provide a contact cavity. Slotsare formed in the oval wall 72 to accept the fixed terminal 26. On eachside of the long portion of the external surface of the oval wall 72, apair of posts are formed in opposed relation with each other. Each posthas an extension formed therewith to provide a shoulder. The two postsprovide a channel therebetween. A triangular projection 76 extends fromeach of the short sides of the upstanding wall 72 with its apex directedaway from the plane of the base portion 70. The base of the projection76 provides an engagement shoulder 77. A ringlike wall 78 extendsupwardly from the base 70 within the area defined by the wall 72 andincludes extensions which act as seats for the fixed contacts 26, in thenormally open design (not shown).

The seal element 22 comprises a circular seal portion 80 having anengagement portion 82 extending from each side and having a hole 84extending centrally therethrough. A lip surrounds the hole 84 on theside opposed to that from which the engagement portions extend. Thefixed terminals 26 comprise a terminal ponion and a contact portionwhich are a continuation thereof and which have a contact 86 formedtherefrom, and bent in angular relation therewith. The movable contact28 is generally rectangular in configuration having a domed-shapedprotuberance 88 and a pair of wings bent in angular relation to theremaining portion of the terminal 26.

The contact assembly is put together by placing the contact spring 30,into the cavity of the case 24 with the spring end within the ringlikewall 78. The protuberance 88 of the movable contact 28 is fitted intothe other terminal end of the contact spring 30. The fixed terminals 26are placed into the slots in the oval wall 72 with the contact 86 buttedagainst the movable contact 28 and the terminal portion extending beyondthe area of the case 24 in right angle relation to the axis thereof. Theseal element 22 is engaged to the case 24 by passing the engagementportion 82 into the channel formed by the posts and by engaging theengagement portion 82 with the shoulder thereby placing the hole 84directly over the cup of the protuberance 88.

The plunger assembly is brought together by placing the plunger spring16 within the cavity of the inner plunger 12 and then passing the innerplunger 12, closed end first, through the hole of the outer plunger 14until the annular flange 32 of the inner plunger 12 butts against thecircumferential shoulder 34 of the outer plunger. The rod portion 40 ofthe divider 18 is passed into the plunger spring 16 and the flange 36 ofthe outer plunger 14 is passed within the wall 44 flexing it outwardlyuntil the tongues 46 engage behind the flange 36 locking the assemblytogether.

We can now take the plunger assembly and pass it through the aperture 52of the plunger holder 48 so that both the inner and outer plungers passthrough the aperture and the forward edge of the divider 18 buttsagainst the surface adjacent the aperture 52. The outer surface of thewall 44 movably engages against the arced guides of the plunger holder48 and also against the inner surface of the legs 54. The contactassembly is passed between both the extension portions 62 until theengagement shoulder 77 of the triangle projections 76 engage within therectangular openings 64 and the two terminal portions extend adjacentthe wings of the external portions 62, completing the switch. The postportions 42 of the divider 18 are passed through the hole 84 in the sealelement 22 and then into the cup formed by the protuberance 88 of themovable contact 28.

To actuate the switch, an axial force is applied on the inner plunger 12which force is immediately transmitted to the post portion 42 of thedivider 18, which in turn displaces the movable contact 28 andcompresses the contact spring 30. in other words the whole plungerassembly (i.e. the inner plunger, plunger spring, outer plunger, anddivider) moves as a unit initially. As the axial force continues, theinner plunger 12 is telescoped within the outer plunger 14 until theouter surface of the inner plunger 12 is on the same plane as the outerplunger !4. At this time continued force will cause the inner and outerplungers to move together into the body 20 for a predetermined distance.It may be possible for the outer plunger 14 to move first orsimultaneously with the inner plunger 12. This allows us an amount ofplunger overtravel, say one-half inch, after actuation of the switch,while maintaining a short switch length behind the bezel.

The purpose of the plunger assembly is to avoid the necessity ofbalancing the plunger and the contact spring and to eliminate anypretravel prior to actuation of the contact spring.

With reference to the foregoing description it is to be undetstood thatwhat has been disclosed herein represents an embodiment of the inventionand is to be construed as illustrative rather than restrictive in natureand that the invention is best described by the following claims.

We claim:

1. A switch comprising a body, a plunger assembly, and a contactassembly, the plunger assembly including a first plunger, a secondplunger, a plunger spring and a divider, the first plungertelescopically engaging the second plunger, the second plunger engagedto the divider .and axially movable therein and the plunger springengaged between the first plunger and the divider, the plunger assemblymovably associated with the body, the contact assembly having a fixedcontact, a movable contact and the divider having means of engaging themovable contact said contact assembly engaged to the housing.

2. A switch as set forth in claim 1 wherein the contact assembly has acontact spring urging the movable contact toward the divider.

3. A switch as set forth in claim 2 wherein the force needed to deflectthe contact spring is less than the force needed to deflect the plungerspring.

4. A switch as set forth in claim 3 wherein the divider comprises a baseportion having a rod portion extending from one side and a post portionextending from the other side and a wall extending upwardly from thebase portion in spaced circumscribed relation to the rod portion and therod portion engaged within the plunger spring and the post portionengaging the movable contact.

5. A switch as set forth in claim 4 wherein a seal element is interposedbetween the plunger assembly and the contact assembly and the sealelement has an aperture portion therethrough through which the postportion engages the movable contact.

* l l l

1. A switch comprising a body, a plunger assembly, and a contactassembly, the plunger assembly including a first plunger, a secondplunger, a plunger spring and a divider, the first plungertelescopically engaging the second plunger, the second plunger engagedto the divider and axially movable therein and the plunger springengaged between the first plunger and the divider, the plunger assemblymovably associated with the body, the contact assembly having a fixedcontact, a movable contact and the divider having means of engaging themovable contact said contact assembly engaged to the housing.
 2. Aswitch as set forth in claim 1 wherein the contact assembly has acontact spring urging the movable contact toward the divider.
 3. Aswitch as set forth in claim 2 wherein the force needed to deflect thecontact spring is less than the force needed to deflect the plungerspring.
 4. A switch as set forth in claim 3 wherein the dividercomprises a base portion having a rod portion extending from one sideand a post portion extending from the other side and a wall extendingupwardly from the base portion in spaced circumscribed relation to therod portion and the rod portion engaged within the plunger spring andthe post portion engaging the movable contact.
 5. A switch as set forthin claim 4 wherein a seal element is interposed between the plungerassembly and the contact assembly and the seal element has an apertureportion therethrough through which the post portion engages the movablecontact.